package com.da.netty.websocket;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.stream.ChunkedWriteHandler;

public class MyWebServer {
    public static void main(String[] args) throws Exception {
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            //创建服务器端的启动对象，配置参数
            ServerBootstrap bootstrap = new ServerBootstrap();
            //使用链式编程来进行设置
            bootstrap.group(bossGroup, workerGroup)
                .channel(NioServerSocketChannel.class)
                .childHandler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel ch) throws Exception {
                        ChannelPipeline pipeline = ch.pipeline();
                        //因为基于http协议，使用http的编码和解码器
                        pipeline.addLast(new HttpServerCodec());
                        //是以块方式写，添加ChunkedWriteHandler处理器
                        pipeline.addLast(new ChunkedWriteHandler());
                        /**
                         说明
                         1. http数据在传输过程中是分段, HttpObjectAggregator ，就是可以将多个段聚合
                         2. 这就就是为什么，当浏览器发送大量数据时，就会发出多次http请求
                         */
                        pipeline.addLast(new HttpObjectAggregator(8192));
                        /**
                         说明
                         1. 对应websocket ，它的数据是以 帧(frame) 形式传递
                         2. 可以看到WebSocketFrame 下面有六个子类
                         3. 浏览器请求时 ws://localhost:7000/hello 表示请求的uri
                         4. WebSocketServerProtocolHandler 核心功能是将 http协议升级为 ws协议 , 保持长连接
                         5. 是通过一个 状态码 101
                         */
                        pipeline.addLast(new WebSocketServerProtocolHandler("/hello"));
                        //自定义的handler ，处理业务逻辑
                        pipeline.addLast(new MyTextWebSocketHandler());
                    }
                });

            //启动服务器
            ChannelFuture cf = bootstrap.bind(7000).sync();
            cf.channel().closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}
